How many openings does a typical (national/international level) tournament player usually know and play?
For instance: in a tournament, can I expect that a player will either open
1.e4 consistently when they have white? And, if black plays (for instance)
1...e6, can I expect their move 2 to be always the same? How long of an opening line will they typically follow without changes (given the opportunity)?
Or maybe they have a single opening that they play 80% of the time, for instance, and then they change completely when they feel like doing something different?
I am not speaking about top-level matches such as a world champion match, where many matches between the same two players are played with a lot of preparation, and I can expect them to vary a bit more.